Binary Paths to Type Ia Supernovae Explosions: The Highlights

TL;DR

This paper reviews the current state of research on Type Ia supernova progenitors, highlighting the debate between Single and Double Degenerate models, observational challenges, and unresolved questions about their origins.

Contribution

It summarizes recent observational and theoretical challenges in identifying the main progenitor channels for Type Ia supernovae.

Findings

Paucity of Super-Soft Sources challenges existing models

Uncertainty remains on the dominant progenitor channel

Luminosity dependence on host galaxy age is unresolved

Abstract

This Symposium was focused on the hunt for the progenitors of Supernovae of Type Ia. Is there a main channel for the production of SNeIa? If so, are these elusive progenitors Single Degenerate or Double Degenerate systems? Although most participants seemed to favour the Single Degenerate channel, there was no general agreement on the type of binary system at play. An observational puzzle that was highlighted was the apparent paucity of Super-Soft Sources in our Galaxy and also in external galaxies. The Single Degenerate channel (and as it was pointed out, quite possibly also the Double Degenerate channel) requires the binary system to pass through a phase of steady nuclear burning. However, the observed number of Super-Soft sources falls short by a factor of up to 100 in explaining the estimated birth rates of SNeIa. Thus, are these Super-Soft sources somehow hidden away and radiating at different wavelengths or are we missing some important pieces of this puzzle that may lead to the elimination of a certain class of progenitor? Another unanswered question concerns the dependence of SNeIa luminosities on the age of their host galaxy. Several hypotheses were put forward, but none was singled out as the most likely explanation. It is fair to say that at the end of the Symposium the definitive answer to the vexed progenitor question remained is well and truly wide open.